Journalists today scored a small victory against Gina Rinehart, whose company is trying to force The West Australian newspaper and one of its journalists to reveal confidential sources as part of a billion-dollar family feud.

WA's Supreme Court ordered today that Hancock Prospecting will have to supply documents explaining why subpoenas on the paper and Walkley Award-winning journalist Steve Pennells to reveal their sources were relevant to a family feud over the Hancock family trust.

"You say they can raise an objection on the grounds of irrelevance but they don't have the information to do it with," he told the court.

Hancock Prospecting's lawyers argued the newspaper was a third party to the dispute and should not have access to confidential documents.

The three children fighting Ms Rinehart for control of the multi-billion family trust have withdrawn their support of the newspaper in opposing the subpoenas, the court heard today.

Hancock Prospecting's lawyers also raised concerns about the newspaper's in-house counsel gaining access to confidential documents concerning the case, because of the nature of the newspaper business.

Outside court, The West Australian editor Brett McCarthy said the newspaper would continue to fight the subpoenas, the contents of which the court heard were, "oppressively broad".

The subpoena requests all letters, faxes, emails, text messages, legal advices,memorandums, text messages or other communitcations Mr Pennells has sent to or received from Ms Rinehart's three estraged children from September 4.

All notes or recordings Mr Pennels, or any other journalist from The West Australian has, which relate to topics including Ms Rinehart, the ongoing family court proceedings, The Hope Margaret Hancock Trust, The Hope Downs Deed and Hancock Prospecting, have also been requested.

"We'll continue to do everything that we can as a newspaper to not have to reveal any confidential sources that any of our reporters may or may not have," Mr McCarthy said.

"That's a long established practice and something that we believe in and that we'll fight for."

The paper's parent company Seven West Media has recently announced plans to establish an alternative to the Press Council.

Lawyers for Hancock Prospecting told the court the West's request for proof of relevance was a "fishing exercise", claiming the newspaper did not already have strong enough grounds to fight the subpoenas.

Ms Rinehart is a substantial shareholder of Fairfax Media, the owner of this website.